Expanding screw

Abstract

An expanding screw for an expandable dowel sleeve ( 31 ) has a shaft ( 12 ) having a rotation-transmitting element ( 15 ) provided at its first end ( 13 ), at least one first screw thread ( 19 ) extending from its second end ( 17 ), and a thread section ( 21 ) provided in a region of the at least one first thread ( 19 ), spaced from the second end ( 17 ), and having at least one further screw thread ( 23 ).

1. An attachment device, comprising a dowel sleeve ( 31 ) having an expansion region ( 32 ); and means for expanding the dowel sleeve ( 31 ) and having a shaft ( 12 ) with first ( 13 ) and second ends ( 17 ), rotation-transmitting means ( 15 ) provided at the first end ( 13 ), at least one first screw thread ( 19 ) extending from the second end ( 17 ), and at least one further multi-lead screw thread ( 23 ) provided in a thread region ( 21 ) of the at least one first thread ( 19 ) spaced from the second end ( 17 ), an axial extent of the thread region ( 21 ) with the at least one further multi-lead screw thread ( 23 ) being smaller than an axial extent (L) of the expansion region ( 32 ) of the dowel sleeve ( 31 ). 
     
     
       2. An attachment device according to  claim 1 , wherein the at least one further multi-lead screw thread ( 23 ) has a same outer diameter (A) as the at least one first screw thread ( 19 ). 
     
     
       3. An attachment device according to  claim 1 , wherein the at least one further multi-lead screw thread ( 23 ) has a same pitch as the at least one first screw thread ( 19 ). 
     
     
       4. An attachment device according to  claim 1 , wherein the at least one further multi-lead screw thread ( 23 ) has a same flank angle (C) as the at least one first screw thread ( 19 ). 
     
     
       5. An attachment device according to  claim 1 , wherein a core diameter (D 2 ) of the shaft ( 12 ) in the thread region ( 21 ) with the least one further multi-lead screw thread ( 23 ) is greater than a core diameter (D 1 ) of the shaft ( 12 ) in a region ( 18 ) between the thread region ( 21 ) with the at least one further multi-lead screw thread ( 23 ) and the second end ( 17 ) of the shaft ( 12 ). 
     
     
       6. An attachment device according to  claim 1 , wherein the at least one first screw thread ( 19 ) is formed as a round thread in a region ( 18 ) between the thread region ( 21 ) with the at least one further multi-lead screw thread ( 23 ) and the second end ( 17 ) of the shaft ( 12 ). 
     
     
       7. An attachment device according to  claim 1 , wherein at least one of the at least one first screw thread ( 19 ) and the at least one further multi-lead screw thread ( 23 ) is formed in the thread region ( 21 ) with at least one further multi-lead screw thread ( 23 ) as a rounded acme thread. 
     
     
       8. An attachment device according to  claim 1 , wherein both the at least one first screw thread ( 19 ) and the at least one further multi-lead screw thread ( 23 ) are formed as acme threads. 
     
     
       9. An attachment device according to  claim 1 , wherein the rotation-transmitting means ( 15 ) is formed as a screw head ( 14 ) having, at a bottom ( 26 ) thereof, a plurality of spaced from each other, elevations ( 27 ). 
     
     
       10. An expanding anchor according to  claim 1 , wherein the at least one further multi-lead screw thread ( 23 ) is formed as a two-lead thread.